1. Field of the Invention
The subject invention generally relates to a steering column assembly, and more specifically to a collapsible steering column assembly longitudinally moveable along a longitudinal axis in response to an axial load applied thereto.
2. Description of the Prior Art
Collapsible steering column assemblies include a lower jacket telescopically engaging an upper jacket along a longitudinal axis. In response to an impact event, such as a vehicular collision in which a driver impacts a steering wheel coupled to the upper jacket, the upper jacket collapses along the longitudinal axis relative to the lower jacket. The collapsible steering column assemblies include an energy absorption device for absorbing energy during the collapse stroke. Typically, the energy absorption device includes a deformable strip of metal passed through an anvil during the collapse stroke. Accordingly, the energy absorption device dissipates energy transmitted to the upper jacket by deforming the strip of metal as is well known.
The collapsible steering column assemblies may include a pivotable adjustment for adjusting a vertical position of the steering wheel vertically about a tilt axis. The collapsible steering column assemblies may also include a telescope adjustment for adjusting a horizontal position of the steering wheel longitudinally along the longitudinal axis. However, the scope of this disclosure is limited to adjustable steering column assemblies in which the upper jacket and the lower jacket remain positionally fixed relative to each other during adjustment and normal operational use, i.e., the collapsible steering column assembly of the subject disclosure may be longitudinally and pivotably adjustable only by moving both the upper jacket and the lower jacket together as a unit.
Accordingly, the upper jacket is positionally fixed relative to the lower jacket during normal operational use, yet must be moveable along the longitudinal axis during the collapse stroke in response to the collision event. Safety and design criteria require that the upper jacket remain rigidly attached to the lower jacket until a pre-determined axial load is applied along the longitudinal axis to the upper jacket, at which time the upper jacket must release relative to the lower jacket to begin the collapse stroke.